Does the Bible teach that you can LOSE Salvation? (Is OSAS True?)

Our listener asked, “I’m starting to doubt OSAS because I come across some scriptures like Revelation 3:5 and II Corinthians 6:1 and I was wondering does the bible teach that you can lose your salvation. I am going to study it myself I just want to make sure I’m sharing the right thing but I want to know your opinion.”